Total hip replacement procedures are performed over 600,000 times every year worldwide and over 350,000 times a year in the United States. These procedures involve removing bone and cartilage from the diseased hip and replacing it with metal and plastic to give the patient a smooth, articulating, and long-lasting hip. Intra-operatively, the surgeon balances the unique bone anatomy of the patient with limited implant sizing and shaping variations made available by each device manufacturer. To optimize the performance of the hip, the surgeon balances the soft tissue envelope around the hip as well as the mechanical balance of the hip. Achieving this balance within a defined three-dimensional space drives the use of imaging devices, such as intra-operative C-arm x-rays.
An x-ray device outputs images of the patient's pelvic area, the surgeon begins evaluating the leg length, femoral offset, and cup inclination visually. A variation of even a small amount from an optimal position can change the stability, mechanical balance, and potentially the longevity of the hip replacement. Thus, the accuracy of the x-ray image and the analysis thereof are very important stages of the procedure.